Soft Yoke Mooring Arrangement

Abstract

Aspects of the disclosure pertain to single point mooring systems and method used in relation to single point mooring systems wherein, the system divides the restoring weight for the mooring system in two and removes hinges and swivel joints from the gravitational load path suspending the restoring weight.

Claims

1. An arrangement, comprising: at least one mooring support structure configured to be attached to a floating structure; at least one first connection connected to the mooring support structure; a first ballast weight connected to the at least one first bearing; a second ballast weight connected to the at least one first bearing; at least one second connection connected to the first ballast weight and the second ballast weight; at least one yoke connected to the at least one second connection; at least one third connection connected to the yoke; and at least one fourth connection connected to the at least one third connection.

2. The arrangement according to claim 1, wherein the at least one mooring support structure is two mooring support structures.

3. The arrangement according to claim 1, further comprising: pendular tension members located between the mooring support structure and the first and second ballast weight, wherein the tension members are configured to withstand both tension and bending.

4. The arrangement according to claim 3, wherein the first, second, third and fourth connections are part of a load path between one of the yoke and first and second ballast weights and the pendular tension members.

5. The arrangement according to claim 1, wherein the arrangement is configured to be disconnected and reconnected from the floating structure.

6. The arrangement according to claim 5, wherein the disconnection and reconnection occur between the yoke and pendular tension members.

7. The arrangement according to claim 6, wherein the disconnection and reconnection occur at the at least one second connection.

8. The arrangement according to claim 1, wherein the at least one second connection allows rotation around three axes.

9. The arrangement according to claim 1, wherein the at least one first connection allows rotation around two axes.

10. The arrangement according to claim 1, wherein the at least one third connection allows rotation around two axes.

11. The arrangement according to claim 1, wherein the at least one fourth connection allows rotation around one axis.

12. The arrangement according to claim 1, wherein the first and second ballast weight are a single weight.

13. The arrangement according to claim 12, wherein the single weight is located below a surface level of water.

14. The arrangement according to claim 1, wherein the first and the second ballast weight are located below a surface level of water.

15. The arrangement according to claim 1, further comprising: at least one pin, located between the floating structure and the mooring support structure, the at least one pin configured to connect and disconnect the floating structure to the mooring structure.

16. An arrangement, comprising: at least one mooring support structure configured to be attached to a floating structure; a first connection connected to the mooring support structure; at least one ballast weight connected to the at least one first connection; at least one link arm; at least one yoke; at least one additional connection connected to the at least one ballast weight and at least one of the at least one link arm and at least one yoke, the at least one additional connection providing one degree of freedom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

[0047] FIG. 1 shows the industry standard coordinate convention used here, in isometric.

[0048] FIG. 2a shows an isometric view of a typical conventional permanently moored soft yoke mooring system. FIG. 2b shows an isometric view of a typical disconnectably moored conventional soft yoke mooring system.

[0049] FIG. 3a shows a profile view of a typical conventional soft yoke mooring system at rest. FIG. 3b shows a profile view of a typical conventional soft yoke mooring system, displaced by environmental loads to illustrate its operating principal.

[0050] FIG. 4a shows a plan view of a typical conventional soft yoke mooring system at rest. FIG. 4b shows a plan view of a typical conventional soft yoke mooring system displaced by environmental loads to a position which creates a yaw angle between the vessel and yoke x-axes.

[0051] FIG. 5a shows a conventional permanently moored submerged yoke system. FIG. 5b shows a conventional disconnectably moored submerged yoke system, illustrating the connecting pin and mooring cradle of a typical system. FIG. 5c shows a conventional disconnectably moored submerged yoke system, with yoke/ballast weight and link-arm (or chain) assemblies laid on the sea floor. FIG. 5d shows a plan view illustrating the challenge posed by a disconnectably moored submerged yoke conventional system, with ballast weight and link-arm (or chain) as typically laid on the sea floor.

[0052] FIG. 6a shows a profile view of a typical conventional soft yoke mooring system at rest, having one of its y-axis bearings installed between the yoke and ballast tank. FIG. 6b shows a profile view of a typical conventional soft yoke mooring system displaced by environmental loads, having one of its y-axis bearings installed between the yoke and ballast tank.

[0053] FIG. 7a shows a profile view of a conventional mooring system having mechanical linkages and a fulcrum. FIG. 7b shows a plan view of a conventional mooring system having mechanical linkages and a fulcrum.

[0054] FIG. 8a shows a profile view of a conventional mooring system having multiple mechanical linkages and a fulcrum. FIG. 8b shows a plan view of a conventional mooring system having multiple mechanical linkages and a fulcrum. FIG. 8c shows a plan view of a conventional mooring system having multiple mechanical linkages and a fulcrum, displaced by environmental loads to a position which creates a yaw angle between the vessel and link-arm x-axes.

[0055] FIG. 9a shows a profile view of a conventional mooring system having a yoke mounted on the floating structure at rest. FIG. 9b shows a profile view of a conventional mooring system having a yoke mounted on the floating structure displaced by the environment to illustrate its operating principal.

[0056] FIG. 10 shows an isometric view of one aspect of the disclosure illustrating independent ballast weights and x, y and z-axis bearings installed between the ballast weight and yoke.

[0057] FIG. 11 shows a profile view of one aspect of the disclosure, illustrating the x, y and z-axis bearings installed between the ballast weight and yoke, at rest.

[0058] FIG. 12 shows a profile view of one aspect of the disclosure, displaced by environmental loads to illustrate its operating principal.

[0059] FIG. 13 shows a plan view of one aspect of the disclosure, displaced by environmental loads to a position which creates a yaw angle between the vessel and yoke x-axes.

[0060] FIG. 14 shows an isometric view of one aspect of the disclosure, with the x, y and z-axis bearings connected to the link-arms, to create a fulcrum.

[0061] FIG. 15 shows a profile view of one aspect of the disclosure, with the x, y and z-axis bearings connected to the link-arms, to create a fulcrum.

[0062] FIG. 16 shows a profile view of one aspect of the disclosure, with the x, y and z-axis bearings connected to the link-arms, displaced by environmental loads to illustrate its operating principal.

[0063] FIG. 17 shows a plan view of one aspect of the disclosure, with the x, y and z-axis bearings connected to the link-arms, displaced by environmental loads to a position which creates a yaw angle between the vessel and yoke x-axes.

[0064] FIG. 18a shows a profile of one aspect of the disclosure, in the permanently moored submerged yoke configuration. FIG. 18b shows one aspect of the disclosure, in the disconnectably moored submerged yoke configuration, with the yoke on the sea floor and the x, y and z-axis bearings and ballast weights remaining attached to the floating structure. FIG. 18c shows a plan view illustrating the ability to reorient the yoke facilitated by configuring disconnectably moored submerged yoke arrangement, with ballast weight and link-arm (or chain) remaining with the floating structure during disconnection.

[0065] FIG. 19a shows a profile view of one aspect of the disclosure in a submerged ballast weight fulcrum mooring configuration. FIG. 19b shows a profile of one aspect of the disclosure in a submerged ballast weight fulcrum mooring system in the disconnected condition.

[0066] FIG. 20 shows the x, y and z-axis bearing assembly of one aspect of the disclosure, with the removable pin closest to the ballast weight or fulcrum side.

[0067] FIG. 21 shows the x, y and z-axis bearing assembly of one aspect of the disclosure, with the removable pin closest to the yoke side.

[0068] FIG. 22 shows the x, y and z-axis bearing assembly of one aspect of the disclosure, with a collet connector to be attached to the ballast weight or fulcrum.

[0069] FIG. 23 shows the x, y and z-axis bearing assembly of one aspect of the disclosure, with a collet connector to be attached to the ballast weight or fulcrum, angled to facilitate collet connector pull-in.

[0070] FIG. 24 shows the x, y and z-axis bearing assembly of one aspect of the disclosure, with a collet connector to be attached to the yoke, to minimize weight handled during disconnection and reconnection.

[0071] FIG. 25 shows the disconnection-reconnection storyboard of one aspect of the disclosure, using the bearing assembly of FIG. 21.

[0072] FIG. 26 shows the disconnection-reconnection storyboard of one aspect of the disclosure, using the bearing assembly of FIG. 22.

[0073] FIG. 27 shows the disconnection-reconnection storyboard of one aspect of the disclosure, using the bearing assembly of FIG. 23, connected to the ballast weight.

[0074] FIG. 28 shows the disconnection-reconnection storyboard of one aspect of the disclosure, using the bearing assembly of FIG. 23, connected to the link-arm.

[0075] FIG. 29 shows the disconnection-reconnection storyboard of one aspect of the disclosure, using the bearing assembly of FIG. 24.

[0076] FIG. 30 shows pull-in for storage of the ballast weight while suspended from the mooring support structure, after disconnection and is a continuation of FIG. 29.

[0077] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures (“FIGS”). It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

[0078] In the following, reference is made to embodiments of the disclosure. It should be understood, however, that the disclosure is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the claims except where explicitly recited in a claim. Likewise, reference to “the disclosure” shall not be construed as a generalization of inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the claims except where explicitly recited in a claim.

[0079] Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first”, “second” and other numerical terms, when used herein, do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0080] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, coupled to the other element or layer, or interleaving elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no interleaving elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed terms.

[0081] Some embodiments will now be described with reference to the figures. Like elements in the various figures will be referenced with like numbers for consistency. In the following description, numerous details are set forth to provide an understanding of various embodiments and/or features. It will be understood, however, by those skilled in the art, that some embodiments may be practiced without many of these details, and that numerous variations or modifications from the described embodiments are possible. As used herein, the terms “above” and “below”, “up” and “down”, “upper” and “lower”, “upwardly” and “downwardly”, and other like terms indicating relative positions above or below a given point are used in this description to more clearly describe certain embodiments.

[0082] FIGS. 10 through 17 show one example non-limiting embodiment of an arrangement of the disclosure. As will be understood by a person of skill in the art, as used on the detailed description, when the term of a “connection” is described, different types of structural connections may be substituted. As such, when the use of the word “bearing” is presented, if the description discloses that the “bearing” has two degrees of freedom, two different bearings may be used to provide the required degrees of freedom. As will be also understood, a different type of “connection” may be used, not using a “bearing” but providing the necessary number of degrees of freedom discussed. Compared with the conventional soft yoke mooring system, described above, aspects of the disclosure provided herein have a soft yoke mooring arrangement with specific modifications:

[0083] f. The single ballast weight (9) of conventional apparatus described above in relation to FIGS. 1 to 9 is replaced by two independent weights (109, 209). This allows each weight (109,209) to swing independently and provide restoring loads and moments exactly as described in the soft yoke mooring system, however, since the two weights (109,209) are separate from one another on the floating structure side (104,204), they are not obligated to rotate about the z-axis relative to the floating structure (104,204) and support structure (111,211), as was the case with the single ballast weight (9).

[0084] g. Compared to the conventional systems shown in FIGS. 2 through 5, the x-axis and y-axis hinges and z-axis swivels (7) are moved from the pendular tension member load path, just above the ballast weight (9) to between the yoke (103, 203) and ballast weight (109,209), with the swivel providing freedom of rotation about the x-axis now integral with the yoke. The x-axis and y-axis hinges and z-axis swivel (107,207) are therefore not in the load path supporting the weights (109,209) and only carry the restoring force loads which is a fraction of the weight load. This enables a reduction in the wear, size, weight and cost of those components (107,207).

[0085] h. In lieu of pendular tension members (110) to support the ballast weight (109), two independent rigid pendular tension member fulcra (210) may be employed which are capable of withstanding not only tension, but bending as well. These rigid pendular tension member fulcra (210) are attached fixedly to the weights (209) and are free to swing about the x-axis and y-axis at upper rigid pendular tension member fulcra hinge points (208), but not free to rotate about the z-axis relative to the floating structure (204) and support structure (211). The advantage of this embodiment is that the rigid pendular tension member fulcra (210) may then act as fulcra in cooperation with their respective weights (209), such that the restoring force transmitted through the x, y and z-axis bearings is multiplied. Taking advantage of this force multiplication fulcrum effect, the amount weight in ballast weights (209) required may be reduced for the mooring restoring force, which reduces the load on the x and y-axis bearings (208) and mooring support structure.

[0086] FIGS. 14 through 17 and 19 show another non-limiting embodiment of the disclosure. In these FIGS., since the tension members (207) are fixedly attached to their respective weights (209), and are capable of withstanding both tension and bending, the yoke (203) may be connected through the hinges and swivel assemblies (207) at any point between the weights (209) and the hinge assemblies (208). This results in a reduction in the weight of the two weights (209) for the same restoring forces. That reduction in weight, allows further reduction in the load path components (208), resulting in further weight and cost reduction.

[0087] The separation distance between the two weights (109,209) is maintained by y-axis direction forces transmitted through the hinges and swivel assemblies (107,207) which are attached to the yoke (103,203). Yoke (103,203) is a rigid isosceles triangular member where opposing sides transmit mooring loads, and base ties hinges and swivel assemblies (107,207) together in the y-direction.

[0088] Because the gravity load of the weights (109,209) are not transmitted by the hinges and swivel assemblies (107,207), the z-axis pin of (107,207) may be removed for disconnection of the floating structure (104,111 or 204,211) from the yoke (103,203), more easily than in arrangements where the disconnection and reconnection is made between the mooring support structure (11) and pendular tension members (10). A collet connector (3011, 3012, and 3014 or 4011, 4012 and 4014) may be utilized to serve as the point at which the disconnection and reconnection is made between the yoke (103 or 203) and the remainder of the x, y and z-axis bearing assembly (107 or 207).

[0089] The arrangement of the disclosure shown in FIGS. 10 through 15 may be lowered beneath the surface of the sea, in a fashion analogous to arrangement shown in FIG. 5. This is shown in FIGS. 18, 19, 26 and 29.

[0090] When used in a disconnectable soft yoke mooring system, the disclosure has further advantages. The aspects of the disclosure facilitate disconnection and reconnection at the x, y and z-axis bearing assembly, leaving the yoke (103,203) with the earth fixed structure (102,202). Since it is approximately 1/10 the weight of the ballast weight (109,209), it is more easily handled, with lighter and cheaper pull-in equipment. The yoke (103,203) is also more easily rotated to facilitate reconnection if the prevailing weather direction changes from disconnection to reconnection, as illustrated by comparing FIG. 5d with FIG. 18c. If submerged, the yoke may be lifted and rotated, or deballasted by injecting air into the yoke (303) through an air-hose (4019) as shown in FIG. 29 and then rotated in a floating condition.

[0091] The disconnection can be made at the z-axis pin (2006) of FIGS. 21 and 25, through coordination of winches (621, 622 and 623) and leaving ropes after sail-away on buoys (630 and 631), as shown in steps 25a through 25e of FIG. 25. The process can then be reversed for reconnection, following steps 25e through 25a.

[0092] A collet connector (3011), with clevis (3005) of FIGS. 22 and 26 may be used for making the connection to the ballast weight (109) using pull-in winch 823 and leaving the pull-in rope tethered on buoys (632 and 633), as shown in steps 26a through 26e of FIG. 26. Reconnection is made following steps 26e through 26a.

[0093] If the collet connector (3011) with clevis (3005) is angled upward, its pull-in operation for connection to the ballast weights (109) or rigid pendular tension member fulcra may be facilitated as shown in FIGS. 23 and 27 or 28.

[0094] To minimize the weight on the yoke (103,203), the collet connectors (4011) with clevis (4005) may be left with the ballast weights (109,209), as shown in FIG. 29. This further enhances the ease with which the yoke may be lifted or deballasted for reconnection. FIG. 30 shows a pull-in arrangement and method for storing the ballast weight after disconnection. This embodiment shows pull-in effected using snatch blocks (4020,4021) and one of the handling winches (1021) with rope (4018).

[0095] The soft yoke mooring system must be designed to withstand and counteract loads from environmental forces (wind, waves and current) associated with what is termed the 100 year event. Depending on location, it is typical that the normal day to day environmental forces and hence, required restoring forces and moments are two orders of magnitude lower than those experienced during the 100 year event. At each one of the hinge points (8) and swivel points (7) normal benign environmental forces still cause the floating structure (4) and link-arms to move and rotate. Because the system must be designed for 100 year events, the weight (9) is very great, on the order of 550 mt per pendant. Hence as the floating structure (4) experiences small perturbations during most of its life, these hinge points are subjected to a load due to the deadweight of (9) which is on the same order of magnitude as the load experienced on the system during the 100 year event. The result of this is wear of the bearings at each hinge point and swivel, reversing fatigue inducing moments and slip-stick noise emanating from the bearings and big heavy, and costly components to withstand the high deadweight, in combination with mooring loads.

[0096] The soft yoke mooring system depends on a ballast weight (9) rigidly connected to its yoke (3). This, in one embodiment, provides x and y-axis hinges (8) at the top of their pendular tension members (10) and x and y-axis hinges and z-axis swivels (8) at the bottom of their pendular tension members (10). Hence bearings are subjected to the full mooring load plus deadweight load of the ballast weight (9).

[0097] The soft yoke mooring system has no mechanical advantage in its use of its ballast weight (9) to generate more mooring restoring force.

[0098] The disconnectable soft yoke mooring system may disconnect at the yoke head connection, leaving the cumbersome assembly of yoke (3), ballast weight (9) and pendular tension members (10) hanging from the mooring support structure (11) or if a submerged disconnectable soft yoke mooring system, at a connection point between the pendular tension members (10) and the mooring support structure (11), leaving an extremely heavy and immobile assembly on the sea floor (12).

[0099] The solutions to the problem, provided herein are to a) remove as many of the hinge and swivel assemblies (7) from the load path of that pendular weight (9) as possible, b) reduce the weight of the pendular weight (9) as much as possible and c) disconnect at a convenient point between the yoke (3) and ballast weight (9).

[0100] Aspects of the disclosure provide those three solutions and solves this problem in three ways:

a. First, by moving the hinge and swivel assemblies (7) from the tensile pendants (10) to the yoke structure (3), those mechanisms are completely removed from the weight (9) load path. Being part of the yoke structure means they now transmit primarily the restoring forces required by the system, which as mentioned before are, under normal operating sea conditions, two orders of magnitude lower than the design requirements of the 100 year event. A similar reduction in pin diameter and assembly weight results in a reduction in the tendency toward slip-stick by two orders of magnitude and a significant reduction in wear and component cost. The yoke ends carry the dead weight of the relatively light yoke structure
b. Secondly, by replacing the tensile pendant members (10) with members resistant to bending, the new rigid pendular tension member fulcra (210) can provide similar restoring force and moment curves vs. displacement as in the conventional soft yoke mooring system, using less weight (9) per pendant, by using mechanical advantage afforded by the rigid pendular tension member fulcra (210). The restoring force may actually be lower for floating structure (204) perturbations. For small perturbations, this results in a higher excursion from the greater angle theta of FIG. 12, which results in more damping energy absorbed by the hull-sea interface and less by the mooring system. If the hinges and swivel assemblies (207) are moved to a point half way between the hinge assemblies (208) and the weights (209), the load on the hinges (208) of the soft yoke mooring arrangement can be roughly half that of the conventional soft yoke mooring system. Hence, they may be designed with smaller pins at the top (208), which not only reduces weight and cost, but also reduces the frictional end moments such that, given the greater stiffness of the rigid pendular tension members compared to the pendular tensile members, reduces the tendency toward slip-stick behavior by roughly an order of magnitude. Although the angular perturbations of the fulcra (210) are roughly twice that of the tensile pendants (10), because the pins are smaller in diameter and the applied load is half that of the tensile pendants for the majority of the operating time, the wear at the bearings is lower in the soft yoke mooring arrangement as well.
c. By disconnecting at the interface between the yoke (3) and ballast weight (9), the yoke (3) which requires handling for reconnection is 1/10.sup.th the weight of the ballast weight (9) and hence may more easily be handled, rotated, lifted and/or deballasted to facilitate reconnection with lighter lifting gear and fewer tugs for floating structure (4) position and heading keeping.

[0101] In one example embodiment, an arrangement is described. The embodiment may comprise at least one mooring support structure configured to be attached to a floating structure and at least one first connection connected to the mooring support structure. The arrangement may also comprise a first ballast weight connected to the at least one first connection, a second ballast weight connected to the at least one first connection and at least one second connection connected to the first ballast weight and the second ballast weight. The arrangement may also comprise at least one yoke connected to the at least one second connection, at least one third connection connected to the yoke; and at least one fourth connection connected to the at least one third bearing.

[0102] In one example embodiment, the arrangement may be configured wherein the at least one mooring support structure is two mooring support structures.

[0103] In one example embodiment, the arrangement may further comprise pendular tension members located between the mooring support structure and the first and second ballast weight, wherein the tension members are configured to withstand both tension and bending.

[0104] In one example embodiment, the arrangement may be configured wherein the first, second, third and fourth connections are part of a load path between one of the yoke and first and second ballast weights and the pendular tension members.

[0105] In one example embodiment, the arrangement may be configured wherein the arrangement is configured to be disconnected and reconnected from the floating structure.

[0106] In one example embodiment, the arrangement may be configured wherein the disconnection and reconnection occur between the yoke and pendular tension members.

[0107] In one example embodiment, the arrangement may be configured wherein the disconnection and reconnection occur at the at least one second connection.

[0108] In one example embodiment, the arrangement may be configured wherein the at least one second connection allows rotation around three axes.

[0109] In one example embodiment, the arrangement may be configured wherein the at least one first connection allows rotation around two axes.

[0110] In one example embodiment, the arrangement may be configured wherein the at least one third connection allows rotation around two axes.

[0111] In one example embodiment, the arrangement may be configured wherein the at least one fourth connection allows rotation around one axis.

[0112] In one example embodiment, the arrangement may be configured wherein the first and second ballast weight are a single weight.

[0113] In one example embodiment, the arrangement may be configured wherein the single weight is located below a surface level of water.

[0114] In one example embodiment, the arrangement may be configured wherein the first and the second ballast weight are located below a surface level of water.

[0115] In one example embodiment, the arrangement may further comprise at least one pin, located between the floating structure and the mooring support structure, the at least one pin configured to connect and disconnect the floating structure to the mooring structure.

[0116] In one example embodiment, an arrangement is disclosed. The arrangement may comprise at least one mooring support structure configured to be attached to a floating structure. The arrangement may also comprise a first connection connected to the mooring support structure. The arrangement may also comprise at least one ballast weight connected to the at least one first bearing and at least one link arm. The arrangement may also comprise at least one yoke and at least one additional connection connected to the at least one ballast weight and at least one of the at least one link arm and at least one yoke, the at least one additional connection providing one degree of freedom.

REFERENCE NUMBERS USED IN THE FIGS

[0117] The following table shows the numbering system used to call out the elements in the FIGS. Where the number has a prime, such as X′ it signifies the component corresponding to X on the side to the negative y direction: [0118] 1 Earth fixation point [0119] 2 Earth fixed structure [0120] 3 Rigid yoke [0121] 4 Floating structure [0122] 5 Main z-axis bearing between earth fixed and rotating structures [0123] 6 Bearings providing rotation about the x and y-axes at the yoke head [0124] 7 Bearings providing rotation about the x, y and z-axes at the lower link-arm [0125] 8 Bearings providing rotation about the x and y-axes at the upper link-arm [0126] 9 Ballast weight for generating restoring force [0127] 10 Link-arm [0128] 11 Mooring support structure [0129] 12 Sea floor [0130] 13 Surface of the water [0131] 15 Additional ballast weight shown in some prior art [0132] 16 Alternate location for y-axis bearing in some prior art, normally installed at component (7) [0133] 17 Yoke connector for disconnectable mooring system [0134] 17a Main connecting pin between mooring tether and mooring cradle [0135] 17b Mooring cradle [0136] 19 Mooring buoy [0137] 21 Mooring leg fixation point to sea floor [0138] 22 Mooring leg [0139] 23 Link-arm [0140] 24 Floating structure [0141] 25 z-axis bearing at buoy [0142] 26 x-axis bearing in link arm [0143] 27 y-axis bearing between pendulum and floating structure [0144] 29 y-axis bearing between link-arm and pendulum [0145] 29 Ballast weight for generating restoring force [0146] 30 Pendulum [0147] 31 Mooring support structure [0148] 32 Sea floor [0149] 33 Surface of the water [0150] 41 Earth fixation point [0151] 42 Earth fixed structure [0152] 43 Link-arm [0153] 44 Floating structure [0154] 45 Main z-axis bearing between earth fixed and rotating structures [0155] 46 y-axis bearing between rotating structure and link-arm [0156] 47 y-axis bearing between yoke and pendulum [0157] 48 x and y-axes bearings between link-arm and pendulum [0158] 49 Ballast weight for generating restoring force [0159] 50 Pendulum [0160] 51 yoke [0161] 52 Sea floor [0162] 53 Surface of the water [0163] 54 y-axis bearings between yoke and floating structure [0164] 55 Buoy [0165] 56 z-axis bearing at buoy [0166] 60 y-axis bearing shown in some prior art [0167] 71 Earth fixation point [0168] 72 Earth tethered structure [0169] 73 Yoke [0170] 74 Floating structure [0171] 75 x, y and z-axes bearings between earth fixed structure and link-arm [0172] 76 x and y-axes between earth fixation point and earth tethered structure [0173] 78 y-axis bearings between yoke and floating structure [0174] 82 Sea floor [0175] 83 Surface of the water [0176] 101 Earth fixation point [0177] 102 Earth fixed structure [0178] 103 Yoke [0179] 104 Floating structure [0180] 105 Main z-axis bearing between earth fixed and rotating structures [0181] 106 Bearings providing rotation about the x and y-axes at the yoke head [0182] 107 Bearings providing rotation about the x, y and z-axes between the yoke and ballast weight [0183] 108 Bearings providing rotation about the x and y-axes at the upper link-arm [0184] 109 Ballast weight for generating restoring force [0185] 110 Pendular tension member [0186] 111 Mooring support structure [0187] 112 Sea floor [0188] 113 Surface of the water [0189] 117 Connector between yoke and ballast weight bearings [0190] 201 Earth fixation point [0191] 202 Earth fixed structure [0192] 203 Yoke [0193] 204 Floating structure [0194] 205 Main z-axis bearing between earth fixed and rotating structures [0195] 206 Bearings providing rotation about the x and y-axes at the yoke head [0196] 207 Bearings providing rotation about the x, y and z-axes between the yoke and rigid pendular tension member fulcrum [0197] 208 Bearings providing rotation about the x and y-axes at the upper rigid pendular tension member fulcrum [0198] 209 Ballast weight for generating restoring force [0199] 210 Rigid pendular tension member fulcrum [0200] 211 Mooring support structure [0201] 212 Sea floor [0202] 213 Surface of the water [0203] 217 Connector between yoke and rigid pendular tension member fulcrum bearings [0204] 621 Yoke handling winch and rope [0205] 622 Removable z-axis pin handling winch and rope [0206] 623 Bearing assembly handling winch and rope [0207] 630 Buoy on yoke side of yoke handling rope [0208] 631 Buoy on winch side of yoke handling rope [0209] 632 Buoy on collet connector side of collet connector pull-in rope [0210] 633 Buoy on winch side of collet connector pull-in rope [0211] 723 Collet connector pull-in winch and rope [0212] 816 Collet connector pull-in sheave [0213] 823 Collet connector pull-in winch and rope [0214] 923 Collet connector pull-in winch and rope [0215] 1001 x-axis bearing housing [0216] 1002 Yoke clevis [0217] 1003 y-axis pin between yoke clevis and mooring connector [0218] 1004 Mooring connector [0219] 1005 Ballast weight or rigid pendular tension clevis [0220] 1006 Removable z-axis pin between connector and ballast weight or rigid pendular tension member fulcrum [0221] 1007 Index stop [0222] 1007a Index stop retracted [0223] 1007b Index stop in operating position [0224] 1008 Padeye for handling yoke during disconnection and reconnection [0225] 1010 Padeye for handling removable z-axis pin [0226] 1023 Collet connector pull-in winch [0227] 1021 Yoke handling winch [0228] 2002 Yoke clevis [0229] 2003 y-axis pin between mooring connector and ballast weight or rigid pendular tension member fulcrum [0230] 2004 Mooring connector [0231] 2005 Clevis of ballast weight or rigid pendular tension member fulcrum [0232] 2006 Removable z-axis pin between connector and ballast weight or rigid pendular tension member fulcrum [0233] 2007 Index stop [0234] 2007a Index stop retracted [0235] 2007b Index stop in operating position [0236] 2009 Padeye or handling bearing assembly during disconnection and reconnection [0237] 2010 Padeye for handling removable z-axis pin [0238] 3002 Yoke clevis [0239] 3003 y-axis pin between mooring connector and collet connector [0240] 3004 Mooring connector [0241] 3005 Collet connector clevis [0242] 3006 z-axis pin between yoke clevis and mooring connector [0243] 3011 Collect connector hub [0244] 3012 Collet connector socket [0245] 3013 Collet connector press ring [0246] 3014 Collet connector finger [0247] 3015 Collet connector pull-in padeye [0248] 4001 x-axis bearing housing [0249] 4002 Collet clevis [0250] 4003 y-axis pin between mooring connector and ballast weight or rigid pendular tension member fulcrum [0251] 4004 Mooring connector [0252] 4005 Ballast weight or rigid pendular tension member fulcrum [0253] 4006 z-axis pin between collet clevis and mooring connector [0254] 4009 Padeye for handling bearing and collet hub assembly during disconnection and reconnection [0255] 4011 Collet connector hub [0256] 4012 Collet connector socket [0257] 4013 Collet connector press ring [0258] 4014 Collet connector finger [0259] 4015 Collet connector pull-in padeye [0260] 4016 Collet connector pull-in sheave [0261] 4017 Collet connector pull-in rope [0262] 4018 Yoke handling rope [0263] 4019 Air hose for deballasting yoke [0264] 4020 Lower snatch block for ballast tank pull-in [0265] 4021 Upper snatch block for ballast tank pull-in

[0266] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0267] While embodiments have been described herein, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments are envisioned that do not depart from the inventive scope. Accordingly, the scope of the present claims or any subsequent claims shall not be unduly limited by the description of the embodiments described herein.